Possible to use a wireless router as a range extender for another wireless router?

[sitheris]

I just got Verizon FIOS, they gave us a wireless router with the install, but they put it in the basement. My room is 3 floors up, so i have horrible signal. I was wondering if I could use another wireless router I have (wrt54gx) to act as a range extender? I would put the router on the middle level of my house for best coverage.

My problem is I don't know how to tell the wrt54gx how to wirelessly connect to the FIOS router.

Would I have to run cable between the two routers for this to work? That would kind of defeat the purpose..